Collapsible ladders are utilised because of the convenience they provide. They may be transported easily, such as in the trunk of a car, and may be carried and erected by one man. It is beneficial for such ladders to collapse to the smallest possible size, whilst still allowing them to be erected to a useful height.
Reducing the physical dimensions to produce the smallest collapsed size has the downside of reducing the width of the footprint when the ladder is erected. A narrower footprint reduces the stability of the ladder, the degree of instability being more noticable the taller the ladder.
Previous solutions to this include the provision of removable feet located at the bottom of each stile which serve to widen the foot print of the ladder, but these are cumbersome to attach or remove each time the ladder is collapsed or erected for transport.